I am trying to get an Exchange 2013 server to co-exist peacefully with Exchange 2007 and Lync 2013 and its been a few months of head bashing with little progress. I am currently having issues with Lync 2013 client prompting for credentials and not accepting them, nor locking out the AD account if intentionally putting them in incorrect more than 3 times (our AD lockout Policy). Lync 2013's configuration information shows that EWS Internal and EWS External URL are blank. This lead me to investigate the autodiscover service running on Exchange 2013.
Now I am in test mode, so on a spare computer I have a modified hosts file containing the new Exchange 2013 IP address for mail, autodiscover, webmail.
I can ping autodiscover.domain.com and I get the Exchange 2013 server's IP address. In Outlook if I right click on the tray icon and do a Test E-Mail AutoConfiguration, it constantly asks me for password, despite putting that password in correctly. If I cancel it just leaves me with "Unable to determine your settings!". I think this is the root cause as to why LYNC is not obtaining the Exchange information.
In Internet Explorer if I browse to https://autodiscover.domain.com/autodiscover/autodiscover.xml, I get the standard Outlook Web App screen. I can log in here but its OWA not the autodiscover file I was expecting.
On Exchange 2013 IIS, I checked the Default Web Site and there are no redirects. I also checked the Autodiscover directory and there are no redirects there either.
I am at a complete loss as to what to go.
The other oddity is that Autodiscover seems to work to initially create an Outlook Profile. In fact it kept BREAKING outlook (requiring endless password prompts). I would have to go into Outlook Anywhere proxy settings and change the authentication from Basic to NTLM. It would fix it, but next time you fire up Outlook it would change it back to Basic! So the InternalClientAuthenticationMethod was already set to NTLM, so even though I am INTERNAL, I also had to run Set-OutlookAnywhere -Identity: "EMAIL\rpc (Default Web Site)" -ExternalClientAuthenticationMethod NTLM . Now its not changing it back. I just hope this didn't break EXTERNAL Outlook Anywhere through IIS reverse proxy.